<?php

/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Feed
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Abstract.php 23775 2011-03-01 17:25:24Z ralph $
 */

/**
 * @see Zend_Feed_Element
 */
require_once 'Zend/Feed/Element.php';

/**
 * The Zend_Feed_Abstract class is an abstract class representing feeds.
 *
 * Zend_Feed_Abstract implements two core PHP 5 interfaces: ArrayAccess and
 * Iterator. In both cases the collection being treated as an array is
 * considered to be the entry collection, such that iterating over the
 * feed takes you through each of the feed.s entries.
 *
 * @category   Zend
 * @package    Zend_Feed
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
abstract class Zend_Feed_Abstract extends Zend_Feed_Element implements Iterator, Countable {
	/**
	 * Current index on the collection of feed entries for the
	 * Iterator implementation.
	 *
	 * @var integer
	 */
	protected $_entryIndex = 0;
	
	/**
	 * Cache of feed entries.
	 *
	 * @var array
	 */
	protected $_entries;
	
	/**
	 * Feed constructor
	 *
	 * The Zend_Feed_Abstract constructor takes the URI of a feed or a
	 * feed represented as a string and loads it as XML.
	 *
	 * @param  string $uri The full URI of the feed to load, or NULL if not retrieved via HTTP or as an array.
	 * @param  string $string The feed as a string, or NULL if retrieved via HTTP or as an array.
	 * @param  Zend_Feed_Builder_Interface $builder The feed as a builder instance or NULL if retrieved as a string or via HTTP.
	 * @return void
	 * @throws Zend_Feed_Exception If loading the feed failed.
	 */
	public function __construct($uri = null, $string = null, Zend_Feed_Builder_Interface $builder = null) {
		if ($uri !== null) {
			// Retrieve the feed via HTTP
			$client = Zend_Feed::getHttpClient ();
			$client->setUri ( $uri );
			$response = $client->request ( 'GET' );
			if ($response->getStatus () !== 200) {
				/**
				 * @see Zend_Feed_Exception
				 */
				require_once 'Zend/Feed/Exception.php';
				throw new Zend_Feed_Exception ( 'Feed failed to load, got response code ' . $response->getStatus () );
			}
			$this->_element = $response->getBody ();
			$this->__wakeup ();
		} elseif ($string !== null) {
			// Retrieve the feed from $string
			$this->_element = $string;
			$this->__wakeup ();
		} else {
			// Generate the feed from the array
			$header = $builder->getHeader ();
			$this->_element = new DOMDocument ( '1.0', $header ['charset'] );
			$root = $this->_mapFeedHeaders ( $header );
			$this->_mapFeedEntries ( $root, $builder->getEntries () );
			$this->_element = $root;
			$this->_buildEntryCache ();
		}
	}
	
	/**
	 * Load the feed as an XML DOMDocument object
	 *
	 * @return void
	 * @throws Zend_Feed_Exception
	 */
	public function __wakeup() {
		@ini_set ( 'track_errors', 1 );
		$doc = new DOMDocument ();
		$status = @$doc->loadXML ( $this->_element );
		@ini_restore ( 'track_errors' );
		
		if (! $status) {
			// prevent the class to generate an undefined variable notice (ZF-2590)
			if (! isset ( $php_errormsg )) {
				if (function_exists ( 'xdebug_is_enabled' )) {
					$php_errormsg = '(error message not available, when XDebug is running)';
				} else {
					$php_errormsg = '(error message not available)';
				}
			}
			
			/**
			 * @see Zend_Feed_Exception
			 */
			require_once 'Zend/Feed/Exception.php';
			throw new Zend_Feed_Exception ( "DOMDocument cannot parse XML: $php_errormsg" );
		}
		
		$this->_element = $doc;
	}
	
	/**
	 * Prepare for serialiation
	 *
	 * @return array
	 */
	public function __sleep() {
		$this->_element = $this->saveXML ();
		
		return array ('_element' );
	}
	
	/**
	 * Cache the individual feed elements so they don't need to be
	 * searched for on every operation.
	 *
	 * @return void
	 */
	protected function _buildEntryCache() {
		$this->_entries = array ();
		foreach ( $this->_element->childNodes as $child ) {
			if ($child->localName == $this->_entryElementName) {
				$this->_entries [] = $child;
			}
		}
	}
	
	/**
	 * Get the number of entries in this feed object.
	 *
	 * @return integer Entry count.
	 */
	public function count() {
		return count ( $this->_entries );
	}
	
	/**
	 * Required by the Iterator interface.
	 *
	 * @return void
	 */
	public function rewind() {
		$this->_entryIndex = 0;
	}
	
	/**
	 * Required by the Iterator interface.
	 *
	 * @return mixed The current row, or null if no rows.
	 */
	public function current() {
		return new $this->_entryClassName ( null, $this->_entries [$this->_entryIndex] );
	}
	
	/**
	 * Required by the Iterator interface.
	 *
	 * @return mixed The current row number (starts at 0), or NULL if no rows
	 */
	public function key() {
		return $this->_entryIndex;
	}
	
	/**
	 * Required by the Iterator interface.
	 *
	 * @return mixed The next row, or null if no more rows.
	 */
	public function next() {
		++ $this->_entryIndex;
	}
	
	/**
	 * Required by the Iterator interface.
	 *
	 * @return boolean Whether the iteration is valid
	 */
	public function valid() {
		return 0 <= $this->_entryIndex && $this->_entryIndex < $this->count ();
	}
	
	/**
	 * Generate the header of the feed when working in write mode
	 *
	 * @param  array $array the data to use
	 * @return DOMElement root node
	 */
	abstract protected function _mapFeedHeaders($array);
	
	/**
	 * Generate the entries of the feed when working in write mode
	 *
	 * @param  DOMElement $root the root node to use
	 * @param  array $array the data to use
	 * @return DOMElement root node
	 */
	abstract protected function _mapFeedEntries(DOMElement $root, $array);
	
	/**
	 * Send feed to a http client with the correct header
	 *
	 * @throws Zend_Feed_Exception if headers have already been sent
	 * @return void
	 */
	abstract public function send();
}
